Heating element

ABSTRACT

The invention relates to a heating element comprising a base body ( 4 ) made of metal, preferably aluminum or stainless steel, the surface ( 10 ) of which is highly polished and corrosion resistant.

The invention concerns a heating body in accord with the principalconcept of Claim 1.

Heating bodies are generally constructed of a base body of unalloyedsteel with a surface coating, in order to attain certain desirablecoloration appearances. In this practice, depending upon the location ofthe said heating body, different coating procedures are used. Thus it ispossible, for example, that heating bodies in residential areas areprovided with a powdery coating or they may be lacquered. Most likely aheating body in a bathroom can be electrically chromed.

The above described procedures and materials have the disadvantage, thatthe surface coating negatively affects the heating capacity of a steelheating body. Thus, for example, an electrically chromed, steel heatingbody, as compared to a lacquered or powder covered steel body, willyield only 20 to 30% as much heat. This poor rendition of heat fromchrome covered steel heating bodies results in the construction of verylarge heating bodies, which in turn, each disadvantageously require alarge space allotment.

The purpose of the present invention is to create a heating body with asimilar, highly reflective surface, which resembles a chromed heatingbody, which sets aside the above named disadvantages and is further,simple and economical to produce.

This purpose is achieved by a heating body with the features of claim 1.

The heating body in accord with the invention has a base body of metal,especially aluminum. The surface of the said invented base body isworked in such a manner, that a conventional electrically applied chromecoating or gilding, for the purpose of and bringing about a highlyreflective surface, can be eliminated. Instead of aluminum, it is alsopossible to make use of any other metal, such as, for instance, a highlyrefined steel.

In accord with the invention, the surface is then of high polish andpossesses a degree of reflectivity of 80% to 100%.

Because of the aluminum, that is to say a metallic, base body and theelimination of the electrical chrome application, the invented heatingbody has a substantially greater thermal efficiency than does theconventional chromed, steel heating body. Thus, a conventional heatingbody, which possesses a chromed coating, when compared to an invented,highly polished heating body constructed of aluminum, exhibits a thermalefficiency which is about 30% to 40% less. In other words, the inventedheating body, when operating at the same heating load, can clearly bemade smaller and less expensively. This is a considerable advantage inbathrooms with predominately less available space.

For the achievement of the desired degree of burnish, the metalconstruction of the invented heating base body is mechanically ground,mechanically polished and chemically and electrochemically polished.

One embodiment of the invented heating body advantageously possesses,for the purpose of increasing the resistance to corrosion and for theretention of the high degree of burnish, an Eloxal coating.

Another embodiment provides, for the increase of resistance tocorrosion, and for the retention of the high degree of burnish, a clearlacquer coating.

Intrinsically, known heating bodies with an aluminum base body are oftenchromed for the purpose of creating a highly reflective surface, whichrequires not only a complicated procedure and is expensive, but further,notably reduces the emission of heat.

Other advantageous designs are the subject of further subordinateclaims.

In the following, the invention is more closely described with the aidof an illustrated presentation of a preferred embodiment.

FIG. 1 shows a perspective view of an invented heating body.

The invented heating body 2 has a base body 4 and two connectionfittings 6, 8 connecting respectively to an inlet line for water supplyand to an outlet line for the removal of the used water. The externalinlet and outlet lines are not shown. The base body 4 has two parallelrunning tubes 12, 14, which are distanced from one another by thecrossover tubes 16. With this arrangement, the water can flow betweenthe two tubes 12, 14, so that, for example, hand towels (not shown) canbe hung on the crossover tubes 16 to be dried.

In accord with the invention, the base body requires no surface coatingfor the attainment of the desired degree of reflectivity, but rather thesurface is worked in such a manner, that both the aesthetic totalimpression of the heating body 2 is increased and the base body is alsoprotected against corrosion and damage.

In a preferred embodiment, the surface possesses a degree ofreflectivity of 80% to 100%.

As an aid for the judgment of the luster of the finish, a reflectometeris applicable, which is in accord with DIN 67 530.

An essential advantage of the invented heating body 2 is, that incomparison to conventional chromed steel heating bodies, it possesses animproved degree of heat transfer. For example, of a chromed heatingbody, the statement is made, that a heat load of some 750 W isdeveloped. Contrary to this, an equally sized aluminum heating body 2develops a heating load of about 1100 W. That is to say, the inventedheating body 2 possesses, size for size, about a 50% greater heatproduction, whereby its high heat transfer capability permits a quickerreaction for the input and output control, such as, for example, mightbe called for by thermostatic regulation. Such an advantage can markedlyreduce the heating costs.

The metal base body 4 of the heating body 2, in keeping with theinvention, is mechanically ground for the achievement of the desireddegree of reflectivity, then mechanically polished and chemically(electro-chemically) brought to a high reflectivity.

The mechanical abrasive treatment is mostly done by rough grinding forthe removal of gross protrusions and depressions of the surface 10. Thisis generally carried out by a grinding disk. In general dry grinding isemployed, whereby the circumferential speed is held to within a range of420 to 1200 RPM.

After the rough grinding, then a secondary grinding takes place. Forthis operation, advantageously, a grinding disk arrangement is againused wherein the laminated disks are impregnated with special clay. The60 to 120 mesh clay is impregnated into a fabric which can be of cloth,sheepskin, or muslin. The disks may turn within a range of 1500 to 1800RPM. However, even a rotation speed up to 3000 RPM may be used.

Subsequent to the secondary grinding, fine abrasive treatment takesplace. This can also be known as pre-polishing. Normally, the disks forthis purpose, as described above, can be of felt, sheepskin or bias cutmuslin fabric with impregnated 100 to 200 mesh clay. The operation iscooled by air flow. The circumferential speed lies somewhere in theranges as given above, although it may be slightly increased.

After the mechanical grinding, the surface 10, for the removal ofabrasion traces, and for the acquiring of a luster, is similarlymechanically treated, this time with a polishing disk. The polishingdisk possesses more laminations, preferably of loose or battened cottonmaterial and turns at some 2000 to 2600 RPM. This polishing isoptionally carried out dry or wet. In order that the hardness of thepolishing disk may be changed, it is possible, that among other changesof a fiber count of the cotton material, also cloth, wood or paperinsertions may be interposed between the individual disks.

Care must be taken, in regard to the mechanical polishing of theinvented heating body, that, in particular, no metal particulate are tobe allowed to adhere to the polishing disks, since such inserts, withoutfail, lead to a lessening of the surface quality.

Fundamentally, attention must be given during the mechanical grindingand polishing, that no excessive temperatures are generated and nogouging of the surface takes place. A protection of such temperature canbe brought about, for the safety of the surface, by an appropriatechoice of the speed of rotation, pressure of the abrasive means, as wellas by means of proper design of the said disks or by the use of abrasiveor polishing means such as greases, oil or pastes.

By the employment of abrasive and/or polishing means, the impingement ofthese materials in the surface 10 is to be avoided, since such embeddedmaterials can be released during the next process step and thus impairthe quality of the surface 10.

Further, in a case of large heating bodies 2 with greater surfaces 10,it can be of advantage, to replace the grinding disks with abrasivebelts.

For the achievement of a final luster, the surface 10 is treated, afterthe mechanical phase, chemically or electrochemically. Preference isgiven to the chemical treatment, since such a procedure, counter to theelectrochemical method, such as, for instance, the Erft-works processhas the advantage, that no electrical energy is required. In this way,instead of electrical current, oxidizing agents are used.

Advantageously, the surface 10 is finally electrochemically anodized, ortreated with Eloxal, so that the resistance to corrosion of the saidsurface is increased by an Eloxal-coating. This is especially valuable,if the heating body 2 is to be used in rooms subject to high humidity,such as, for example, bathrooms or, as mentioned above, the heating bodyis to be used for the drying of towels.

By the above, the surface 10 is chemically changed, so that a porousaluminum oxide layer is formed, which is still to be sealed in a finalstep of the process.

It is also possible, that the surface 10, instead of being coated withthe Eloxal layer, receives a finish of a clear lacquer for the increaseof the resistance to corrosion. In this case, the lacquer coating can beapplied by spraying, or in the form of a powder, or by means of a finebrush, or the lacquer can be applied by dipping into a immersion bath.

Disclosed is a heating body with a base body of metal, preferablyaluminum or high quality steel, the surface of which, is caused to be ofhigh reflectivity and resistant to corrosion.

REFERENCE NUMBERS AND CORRESPONDING COMPONENTS

-   2 Heating body-   4 Base body-   6 Connection fitting-   8 Connection fitting-   10 Surface-   12 Parallel tube-   14 Parallel tube-   16 Crossover tube(s)

1. A heating body with a base body (4) constructed of metal, especiallyaluminum, therein characterized, in that the surface (10) of the basebody (4) has a degree of reflectance of approximately 80% to 100%.
 2. Aheating body in accord with claim 1, therein characterized, in that thesurface (10) is mechanically ground, in particular by, respectivelyrough grinding, grinding, fine grinding i.e. prepolishing, thenmechanically polished and chemically polished.
 3. A heating body inaccord with claim 2, therein characterized, in that the surface (10) iselectrochemically anodized that is, treated with Eloxan.
 4. A heatingbody in accord with claim 2, therein characterized, in that the surface(10) possesses a coat of clear lacquer.